I really need to delete a question but I couldn't find it
Most Helpful Guy
You cannot. You can disavow it after a while, effectively severing any connection between your account and it, but that's all. The Mods/admins doesn't take down questions that doesn't violate any terms.2
Most Helpful Girl
Unfortunately you can't delete questions. You can ask the admins to delete it for you, but they will very rarely do so. The best that you can do is to disavow it and hope for the best.
Contact the admins here: http://www.girlsaskguys.com/contact0